Gore stated in an interview for the New York Times that his interest in environmentalism began when he was a teenager:

As I was entering high school, my mother was reading Silent Spring and the dinner table conversation was about pesticides and the environment [...] The year I graduated from college the momentum was building for Earth Day. After Vietnam, as I was entering divinity school, the Club of Rome report came out and the limits to growth was a main issue.[1]

Gore has been involved with the environment for a number of decades. In 1976, after joining the United States House of Representatives, Gore held the "first congressional hearings on the climate change, and co-sponsor[ed] hearings on toxic waste and global warming."[2][3] He continued to speak on the topic throughout the 1980s[4] and was known as one of the Atari Democrats, later called the "Democrats' Greens, politicians who see issues like clean air, clean water and global warming as the key to future victories for their party."[1][5]

In 1989, while still a Senator, Gore published an editorial in the Washington Post, in which he argued

Humankind has suddenly entered into a brand new relationship with the planet Earth. The world's forests are being destroyed; an enormous hole is opening in the ozone layer. Living species are dying at an unprecedented rate.[6]

In 1990, Senator Gore presided over a three-day conference with legislators from over 42 countries which sought to create a Global Marshall Plan, "under which industrial nations would help less developed countries grow economically while still protecting the environment." [7]

The Concord Monitor says that Gore "was one of the first politicians to grasp the seriousness of climate change and to call for a reduction in emissions of carbon dioxide and other greenhouses gases.[8]

As Vice-President, Gore was involved in a number of initiatives related to the environment. He launched the GLOBE program on Earth Day 1994, an education and science activity that, according to Forbes magazine, "made extensive use of the Internet to increase student awareness of their environment".[9] In the late 1990s, Gore strongly pushed for the passage of the Kyoto Protocol, which called for reduction in greenhouse gas emissions.[10][11] He was opposed by the Senate, which passed unanimously (95–0) the Byrd–Hagel Resolution (S. Res. 98),[12] which stated the sense of the Senate was that the United States should not be a signatory to any protocol that did not include binding targets and timetables for developing as well as industrialized nations or "would result in serious harm to the economy of the United States".[13] On November 12, 1998, Gore symbolically signed the protocol. Both Gore and Senator Joseph Lieberman indicated that the protocol would not be acted upon in the Senate until there was participation by the developing nations.[14] The Clinton Administration never submitted the protocol to the Senate for ratification. In 1998, Gore began promoting a NASAsatellite that would provide a constant view of Earth, marking the first time such an image would have been made since The Blue Marble photo from the 1972 Apollo 17 mission. The "Triana" satellite would have been permanently mounted in the L1Lagrangian Point, 1.5 million km away.[15] During this time, he also became associated with Digital Earth.[16]

In 2004, Gore co-launched Generation Investment Management, a company for which he serves as Chair. The company was "a new London fund management firm that plans to create environment-friendly portfolios. Generation Investment will manage assets of institutional investors, such as pension funds, foundations and endowments, as well as those of 'high net worth individuals,' from offices in London and Washington, D.C."[17]

Gore and The Alliance for Climate Protection created the We Can Solve It organization, a web-based program with multiple advertisements on television focused on spreading awareness for climate crisis (global warming) and petitioning for the press putting more attention on the crisis, the government doing more to help the environment, and their ultimate goal is the end to global warming. Although focused mostly upon the United States, and Americans, it is an international petition and effort. It already has over one million signatures.[1]

In recent years, Gore has remained busy traveling the world speaking and participating in events mainly aimed towards global warming awareness and prevention.[18] His keynote presentation on global warming has received standing ovations, and he has presented it at least 1,000 times according to his monologue in An Inconvenient Truth. His speaking fee is $100,000.[19] Gore's global warming presentations in several major cities have sometimes been associated with exceptionally severe cold weather, a juxtaposition since dubbed "the Gore Effect."[20][21] Gore is a vocal proponent of carbon neutrality, buying a carbon offset each time he travels by aircraft.[22] Gore and his family drive hybrid vehicles.[23] In An Inconvenient Truth Gore calls for people to conserve energy.

In 2007, Al Gore was the main non-official representative for the United States in the United Nations Climate Change Conference in Bali, which is a series of discussions that plans to continue where the Kyoto Protocol left off when it expires in 2012.[24] He used a famous World War IIpoem written by Pastor Martin Niemöller to describe how the international community is eerily accomplishing nothing in the face of the greatest crisis in human history.[25] He ended the speech using his famous tag line: "However, political will is a renewable resource."[26]

In this speech, Al Gore says that our dangerous over-reliance on carbon-based fuels is at the core of all three of the economic, environmental and national security crises. Our democracy has become sclerotic at a time when these crises require bold policy solutions.[36]

On September 24, 2008 Gore made the following statements in a speech given at the Clinton Global Initiative:

"If you're a young person looking at the future of this planet and looking at what is being done right now, and not done, I believe we have reached the stage where it is time for civil disobedience to prevent the construction of new coal plants that do not have carbon capture and sequestration."[38]

These remarks were similar to ones he'd made the previous year:

“I can’t understand why there aren’t rings of young people blocking bulldozers,” Mr. Gore said, “and preventing them from constructing coal-fired power plants.”[39]

In March 2010[40] two nonprofit organizations founded by Al Gore, The Alliance for Climate Protection and The Climate Project, joined together, and in July 2011 the combined organization was renamed the Climate Reality Project.[41] In February 2012 the Climate Reality Project organized an expedition to the Antarctic with civic and business leaders, activists and concerned citizens from many countries.[42]

Four main environmental criticisms are regularly leveled at Gore: (1) he has an alleged conflict of interest from his role as both an investor in green-technology companies and as an advocate of taxpayer-funded green-technology subsidies,[43][44] (2) he allegedly makes erroneous scientific claims,[45][46] (3) he consumes excessive amounts of energy,[47] and (4) he allegedly refuses to debate others on the subject of global warming.[48]

In reference to Gore's alleged conflict of interest, some critics have labeled Gore a "carbon billionaire." [49] In response to these criticisms Gore stated that it is “certainly not true” that he is a “carbon billionaire” and that he is "proud to put my money where my mouth is for the past 30 years. And though that is not the majority of my business activities, I absolutely believe in investing in accordance with my beliefs and my values."[50] Gore was challenged on this topic by Tennessee Congresswoman Marsha Blackburn who asked him: "The legislation that we are discussing here today, is that something that you are going to personally benefit from?”[50] Gore responded by stating: "I believe that the transition to a green economy is good for our economy and good for all of us, and I have invested in it." Gore also added that all earnings from his investments have gone to the Alliance for Climate Protection and that "If you believe that the reason I have been working on this issue for 30 years is because of greed, you don’t know me."[50] Finally, Gore told Blackburn: "Do you think there is something wrong with being active in business in this country [...] I am proud of it. I am proud of it."[51]

Criticisms of Gore's allegedly erroneous scientific statements tend to focus on a British High Court's ruling that Gore's Inconvenient Truth documentary was deemed by the court to have nine significant errors.[45] Reference leads to homepage of source not article.

Gore has also been the subject of criticism for his personal use of energy, including his use of private jets[citation needed] and ownership of multiple very large homes.[52] The Tennessee Center for Policy Research (TCPR) has twice criticized Gore for electricity consumption in his Tennessee home. In February 2007, TCPR stated that its analysis of records from the Nashville Electric Service indicated that the Gore household uses "20 times as much electricity as the average household nationwide."[53][54] In reporting on TCPR's claims, MSNBC's Countdown With Keith Olbermann noted that the house has twenty rooms and home offices and that the "green power switch" installed increased their electric bill while decreasing overall carbon pollution.[55] Philosopher A. C. Grayling also defended Al Gore, arguing that Gore's personal lifestyle does nothing to impugn his message and that Gore's critics have committed the ad hominem fallacy.[56]

A few months later, the Associated Press reported on December 13, 2007 that Gore "has completed a host of improvements to make the home more energy efficient, and a building-industry group has praised the house as one of the nation's most environmentally friendly [...] 'Short of tearing it down and starting anew, I don't know how it could have been rated any higher,' said Kim Shinn of the non-profit U.S. Green Building Council, which gave the house its second-highest rating for sustainable design."[57]

Gore was criticized by the TCPR again in June 2008, after the group obtained his public utility bills from the Nashville Electric Service and compared "electricity consumption between the 12 months before June 2007, when it says he installed his new technology, and the year since then."[58][59] According to their analysis, the Gores consumed 10% more energy in the year since their home received its eco-friendly modifications. TCPR also argued that, while the "average American household consumes 11,040 kWh in an entire year," the Gore residence "uses an average of 17,768 kWh per month –1,638 kWh more energy per month than before the renovations."[59] Gore's spokeswoman Kalee Kreider countered the claim by stating that the Gores' "utility bills have gone down 40 percent since the green retrofit." and that "the three-year renovation on the home wasn't complete until November, so it's a bit early to attempt a before-and-after comparison."[60] She also noted that TCPR did not include Gore's gas bill in their analysis (which they had done the previous year) and that the gas "bill has gone down 90 percent [...] And when the Gores do power up, they pay for renewable resources, like wind and solar power or methane gas."[61]Media Matters for America also discussed the fact that "100 percent of the electricity in his home comes from green power" and quoted the Tennessee Valley Authority as stating that "[a]lthough no source of energy is impact-free, renewable resources create less waste and pollution."[62]

Furthermore, organizations such as PETA have criticized Gore for not advocating vegetarianism.[63] Gore responded by stating, "I'm not a vegetarian, but I have cut back sharply on the meat that I eat [...] It's absolutely correct that the growing meat intensity of diets around the world is one of the issues connected to this global crisis - not only because of the CO2 involved, but also because of the water consumed in the process." [64]

Some have argued that Gore refuses to debate the topic of global warming. Bjørn Lomborg asked him to debate the topic at a conference in California. Gore replied that he would not, stating that "The scientific community has gone through this chapter and verse. We have long since passed the time when we should pretend this is a ‘on the one hand, on the other hand’ issue,” he said. “It’s not a matter of theory or conjecture, for goodness sake." [65]

Gore starred in the documentary filmAn Inconvenient Truth, released on May 24, 2006. The film documents the evidence for anthropogenicglobal warming and warns of the consequences of people not making immediate changes to their behavior. It is the fourth-highest-grossing documentary in U.S. history.[66]

After An Inconvenient Truth was nominated for an Academy Award, Donna Brazile (Gore's campaign chairwoman from the 2000 campaign) speculated that Gore might announce a possible presidential candidacy for the 2008 election. During a speech on January 31, 2007, at Moravian College, Brazile stated, "Wait till Oscar night, I tell people: 'I'm dating. I haven't fallen in love yet. On Oscar night, if Al Gore has slimmed down 25 or 30 pounds, Lord knows.'"[67] During the award ceremony, Gore and actor Leonardo DiCaprio shared the stage to speak about the "greening" of the ceremony itself. Gore began to give a speech that appeared to be leading up to an announcement that he would run for president. However, background music drowned him out and he was escorted offstage, implying that it was a rehearsed gag,[68][69] which he later acknowledged.[70]

After winning the 2007 Academy Award for Documentary Feature.[71] the Oscar was awarded to director Davis Guggenheim, who asked Gore to join him and other members of the crew on stage. Gore then gave a brief speech, saying, "My fellow Americans, people all over the world, we need to solve the climate crisis. It's not a political issue; it's a moral issue. We have everything we need to get started, with the possible exception of the will to act. That's a renewable resource. Let's renew it."[72]

The official documentary film website is meaningfully called climatecrisis.net [73]

On July 7, 2007, Live Earthbenefit concerts were held around the world in an effort to raise awareness about climate change. The event was the brainchild of Gore and Kevin Wall of Save Our Selves. On July 21, 2007, Gore announced he was teaming with actress Cameron Diaz for a TV climate contest, 60 Seconds to Save the Earth, to gain people's support in solving the climate crisis.[81]

I am deeply honored to receive the Nobel Peace Prize. This award is even more meaningful because I have the honor of sharing it with the Intergovernmental Panel on Climate Change—the world's pre-eminent scientific body devoted to improving our understanding of the climate crisis—a group whose members have worked tirelessly and selflessly for many years. We face a true planetary emergency. The climate crisis is not a political issue, it is a moral and spiritual challenge to all of humanity. It is also our greatest opportunity to lift global consciousness to a higher level.

Gore and Pachauri accepted the Nobel Peace Prize for 2007 in Oslo, Norway on December 10, 2007.[85][86]

In the Lecture he delivered on December 10, 2007 in Oslo, fece to the Royal Highnesses of Norway, to the members of the Norwegian Nobel Committee and to the other ladies and gentlemen, who attended the ceremony for the Nobel prize-giving, he made this surprising statement:

Last September 21, as the Northern Hemisphere tilted away from the sun, scientists reported with unprecedented distress that the North Polar ice cap is "falling off a cliff." One study estimated that it could be completely gone during summer in less than 22 years. Another new study, to be presented by U.S. Navy researchers later this week, warns it could happen in as little as 7 years.

— Al Gore, from the Lecture delivered on December 10, 2007 in Oslo in occasion of the ceremony for the Nobel prize-giving[87]